What force does the boxer exert?

Question

A boxer punches a sheet of paper in mid air, and brings it from rest up to a speed of 26 m/s in 0.05 s. If the mass of the paper is 0.001 kg, what force does the boxer exert on it?

Answer 1

Another way to solve this is to use the Impulse-Momentum theory.

 

F * t = m Δv

F * t = m * (v_f -v_i)

 

Solve for F, the force, and we find

 

F = m * (v_f -v_i) / t

 

Plug everything in and we get

 

F = 0.001 * (26 - 0) / 0.05

F = 0.52 N

 

I hope this helps!

Answer 2

Hey Lane,

 

Firstly let's find the acceleration of the paper sheet

 

a = (v-u) / t

 

where v is the final and u  the initial velocity

 

a = (26-0) / 0.05

 

a = 520 m/s^2

 

Finally we use F= ma to find the force in Newtons

 

F = (0.001) * 520

 

F = 0.520 N

 

thats the force exerted by the boxer on the sheet of paper hope it helps.